The researchers looked at 26 observational studies of nap time among children from birth to age 5. "The most consistent finding was an association between napping and later onset, shorter duration and poorer quality of night sleep, with evidence strongest beyond the age of 2 years," the researchers wrote. They also suggested, "In preschool children presenting with sleep problems, clinicians should investigate napping patterns."

There is a significant body of data on childrens night sleep that show association with a range of important health and psychological outcomes, she said. For example, consistent links between night sleep, but not day sleep, with weight status, including pediatric obesity, are reported. As with adults, disrupted sleep is associated with behavior and cognitive functioning. Children deprived of sleep are less resilient to emotional challenges and function less well in remembering and learning.

Some experts caution against reading too much into the findings.

"There's a lot that we still need to understand about the impact (of napping) on health. The only consistent finding was that children above the age of 2 who don't nap do fall asleep more easily and sleep more consistently throughout the night," said Kelly Glazer Baron, assistant professor of neurology at Northwestern University's Feinberg School of Medicine, to the Huffington Post.

She told Catherine Pearson, "Some people have read (the study) and said, 'Well, that means to sleep better at night, children beyond the age of 2 shouldn't nap. Certainly, by taking away a nap during the day, you will help them sleep more at night because they're just so exhausted. That doesn't mean it's a good thing, though."

Dr. Richard Ferber, director of the Center for Pediatric Sleep Disorders at Boston Children's Hospital, told LiveScience that different children have different sleep needs. LiveScience wrote that Ferber said "the study had a number of limitations. For one, the researchers analyzed studies of children with very different age ranges, who tend to have very different sleep needs. ... The studies also required parents to recall how their children napped, which can be very prone to error."

Thorpe said it is widely acknowledged within the child care sector that napping in preschool children promoted growth. But she said research had shown it instead had a negative impact on night sleep patterns of children 3 and over.

There is consistent high quality data that indicates napping beyond the age of two lengthens the amount of time it takes for a child to fall asleep, she said in a release.